Jeep Garage  - Jeep Forum banner

21 - 32 of 32 Posts

·
Registered
Joined
·
108 Posts
My experience is very similar to yours with our 2015 Summit, my wife does mostly city driving with 2-5 mile trips, we've never seen the DPF message. I do go out of my way to buy diesel at a busy Shell station though, and I follow service interval B because of the frequent short trips.

Using good judgment of how much gas pedal pressure is enough to get you going until the turbo kicks should help reduce soot production, per articles like "Analysis of the Effect of Vehicle, Driving and Road Parameters on the Transient Performance and Emissions of a Turbocharged Truck"


Perhaps you nailed it when you mentioned gas pedal pressure... My wife primarily drives our 2015 and we both pretty much drive like an old lady and have never even tried the Sport Mode. I doubt ours has every been above 70 mph believe it or not. We also go according to service interval B and buy quality fuel, and also have never seen any DPF messages.

I have only one question... shouldn't we be calling it the "diesel pedal" and not "gas pedal"?
 

·
Registered
Joined
·
1,165 Posts
While this driving behavior "may" be good for emissions (Not proven) It certainly isn't good for the engine per se... Diesels like to be worked hot hard and long. That's what helps them break in and reach their sweet spot for performance and best MPG. I have read that these Eco's and other light duty diesels like them, don't begin to even get broken it till they hit roughly 40K miles, unless you do much towing with them…. You can drive them as gingerly as you want, that's your prerogative, but you are not extracting the best out of them unless you are towing or racking up the miles.... JMHO.....
 

·
Registered
Joined
·
108 Posts
While this driving behavior "may" be good for emissions (Not proven) It certainly isn't good for the engine per se... Diesels like to be worked hot hard and long. That's what helps them break in and reach their sweet spot for performance and best MPG. I have read that these Eco's and other light duty diesels like them, don't begin to even get broken it till they hit roughly 40K miles, unless you do much towing with them…. You can drive them as gingerly as you want, that's your prerogative, but you are not extracting the best out of them unless you are towing or racking up the miles.... JMHO.....
I’m not promoting driving them gingerly on short trips, I’m only stating that’s the way we drive ours as well as our 2008 CRD and we haven’t had any trouble. I haven’t heard many people complaining about wearing out an EcoDiesel engine… most all of the complaints are related to emissions, and if driving them gingerly is rumored to help with emission components, perhaps we’re lucky our driving style coincides.
 

·
Registered
Jeep GC
Joined
·
42 Posts
While this driving behavior "may" be good for emissions (Not proven) It certainly isn't good for the engine per se... Diesels like to be worked hot hard and long. That's what helps them break in and reach their sweet spot for performance and best MPG. I have read that these Eco's and other light duty diesels like them, don't begin to even get broken it till they hit roughly 40K miles, unless you do much towing with them…. You can drive them as gingerly as you want, that's your prerogative, but you are not extracting the best out of them unless you are towing or racking up the miles.... JMHO.....
Soot = bad for our emission setup, and the driving behavior mentioned above helps keep soot production down. Not sure which part of that statement you think is not proven; not trying to be confrontational, just curious where the disconnect/lack of understanding on my part is.

Also, I hear a lot of 'diesels like ot be worked hot and hard' statements, but what exactly does that mean? Once the engine is up to its proper operating temperature, how does running it "harder" make it last longer? Maybe we should define what "running it hard" means.
 

·
Registered
Overland ATG ORAII
Joined
·
1,269 Posts
The secret is to take it on long road trips, not idle it a lot and drive it like a Granny around town;).
 

·
Registered
Joined
·
108 Posts
The secret is to take it on long road trips, not idle it a lot and drive it like a Granny around town;).
What defines a "long trip"? They're putting the Ecodiesel into the Wrangler which most folks don't buy for long trips. Most of the Wrangler crowd wants the low end torque while rock climbing (severe stop and go).

Soot is a big enemy. I drive like a granny, but I hardly do any start-stop driving on my "short trips" (~6 miles into town with one stop sign) which helps keep soot low. These types of diesel engines are all over Europe in city driving conditions and are most likely tuned to handle city driving much better than a big rig. I don't think any of us, regardless of our driving habits, can expect true diesel performance and longevity.
 

·
Registered
Overland ATG ORAII
Joined
·
1,269 Posts
DJP2014,
There was more than a small amount of irony in my post mate ;) ;)
 

·
Registered
Joined
·
953 Posts
What defines a "long trip"? They're putting the Ecodiesel into the Wrangler which most folks don't buy for long trips. Most of the Wrangler crowd wants the low end torque while rock climbing (severe stop and go).

Soot is a big enemy. I drive like a granny, but I hardly do any start-stop driving on my "short trips" (~6 miles into town with one stop sign) which helps keep soot low. These types of diesel engines are all over Europe in city driving conditions and are most likely tuned to handle city driving much better than a big rig. I don't think any of us, regardless of our driving habits, can expect true diesel performance and longevity.
The Jeep's will produce plenty of heat while trail riding, and I'm sure the tuning will provide for low-speed regens.

How is it you know you're keeping soot low? You can't compare our engines to the same one used in Europe due to a difference in fuel and tuning. Both make all the difference when it comes to soot production.
 

·
Registered
Joined
·
89 Posts
I think the short commute issue is overrated. There are a lot of owners that use these diesels for short city drives without issue. You just have to educate yourself on the nuances of diesel ownership, as mentioned earlier.
Short drives for a CRD are bad news unless every now and then you are able to take it for a blast down the highway in a lower gear to ensure a regen. Any CRD does not like short trips. In the UK we mostly have CRDs for long trips and a gas car for town driving.
 

·
Registered
Jeep GC
Joined
·
42 Posts
The Jeep's will produce plenty of heat while trail riding, and I'm sure the tuning will provide for low-speed regens.

How is it you know you're keeping soot low? You can't compare our engines to the same one used in Europe due to a difference in fuel and tuning. Both make all the difference when it comes to soot production.
I don't have an exact value of how much soot is being produced personally (broadly speaking though see the study mentioned above) but I'm estimating soot production is low by monitoring the average distance between DPF Regens. It's clear regens happen more often if I drive around town only (about 30% more often than when doing highway only driving), which leads me to believe there's more soot being produced. When I'm in a hurry and speed around during short trips I see the average distance drop, aka more soot.
 

·
Registered
Joined
·
108 Posts
The Jeep's will produce plenty of heat while trail riding, and I'm sure the tuning will provide for low-speed regens.

How is it you know you're keeping soot low? You can't compare our engines to the same one used in Europe due to a difference in fuel and tuning. Both make all the difference when it comes to soot production.
I'm not a soot expert, but I did sleep at a Holiday Inn Express last night... But all kidding aside, I did learn a bit about the DPF filters in 2004 while working for a large European company that manufactures them. Nonetheless since I've never cut ours open, I can only guess that our driving style (short trips, very little start-stop, long trip once a month, no towing, and driving like a granny) has kept soot relatively low, because we've had zero DPF regen messages/keep driving messages, and we've been driving our 2008 CRD for 12 years and the Ecodiesel for 5.

Hammering the throttle is reportedly bad whether you're heading to the highway for that long drive or heading to the store on that short drive. How many miles does it take to get the exhaust system up to steady-state temperature? I wonder whether the "tuning" is dynamic/learned as you drive and not just pre-programmed at the factory to aid in temperature and fuel control to minimize soot.
 

·
Registered
Joined
·
953 Posts
I don't have an exact value of how much soot is being produced personally (broadly speaking though see the study mentioned above) but I'm estimating soot production is low by monitoring the average distance between DPF Regens. It's clear regens happen more often if I drive around town only (about 30% more often than when doing highway only driving), which leads me to believe there's more soot being produced. When I'm in a hurry and speed around during short trips I see the average distance drop, aka more soot.
Keep in mind the concept of a passive regen and how it affects soot percentage during city driving and highway driving. The time spent in passive regen will be much higher during highway driving as a much higher DPF temp is obtained and maintained for a longer duration. Not much passive regen opportunities in city driving.

So it's not just about soot production at any given throttle position. Passive regen will have a lot to do with distance between active regens.

If you don't have a strong grasp of active and passive regens, this theory might sound very foreign to you.
 
21 - 32 of 32 Posts
Top